diff --git a/src/osal.h b/src/osal.h
index a1c8c1f6..be02cf11 100644
--- a/src/osal.h
+++ b/src/osal.h
@@ -181,7 +181,8 @@ static inline void *mdbx_calloc(size_t nelem, size_t size) {
 
 #ifndef mdbx_realloc
 static inline void *mdbx_realloc(void *ptr, size_t bytes) {
-  return LocalReAlloc(ptr, bytes, LMEM_MOVEABLE);
+  return ptr ? LocalReAlloc(ptr, bytes, LMEM_MOVEABLE)
+             : LocalAlloc(LMEM_FIXED, bytes);
 }
 #endif /* mdbx_realloc */